Cooling system and operation method of electric oil pump in cooling system

Abstract

A cooling system 100 includes an electric oil pump 18, an outside air temperature sensor 22, an oil temperature sensor 21, and a controller 30. The controller 30 permits the actuation of the electric oil pump 18 in one of a first case where an oil temperature To is equal to or greater than a first threshold (A) and where an outside air temperature Ta is equal to or greater than a second threshold (B), a second case where the outside air temperature Ta is less than the second threshold (B) and where the oil temperature To is equal to or greater than a third threshold (C) higher than the first threshold (A), and a third case where the oil temperature To is less than the first threshold (A) and where the outside air temperature Ta is equal to or greater than a fourth threshold (D) higher than the second threshold (B).

Description

PRIORITY INFORMATION[0001]The entire disclosure of Japanese Patent Application No. 2013-268384, filed on Dec. 26, 2013, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.TECHNICAL FIELD[0002]The present invention relates to a structure of a cooling system which circulates cooling oil by an electric oil pump, and to an operation method of the electric oil pump.BACKGROUND ART[0003]In an electric vehicle using a motor as a driving source, motor cooling oil is often circulated by an electric nil pump to cool a stator or a rotor. However, if the electric oil pump is operated in to situation where the temperature of the motor does not rise at a low outside air temperature, mileage per charge is reduced. Therefore, a method that keeps the electric oil pump out of operation in this case has been suggested (e.g., see JP 2005-245085 A1).[0004]According to another suggestion, when the outside air temperature is low, it is assumed t...

AI Technical Summary

Benefits of technology

The present invention helps to prevent incorrect detection of an electric oil pump fault and expands the range of operation for the pump. This is achieved by using a simple configuration.

Problems solved by technology

However, it is difficult to directly measure the oil temperature inside the electric oil pump, and providing the temperature sensor in the vicinity of the electric oil pump only to judge the activation of the pump leads to the problem of complication of a cooling system.

However, the control according to these conventional arts has the following problems: A fault is detected in the electric oil pump even if it is not faulty (erroneous detection of a fault), or the operating temperature region of the electric oil pump is excessively restricted to ensure the activation of the electric oil pump.

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